1. Field of the Invention
Aspects of the present invention relate to a method and apparatus to control an audio signal output level, and more particularly, to a method and apparatus to control an audio signal output level of a portable audio device.
2. Description of the Related Art
People frequently listen to music using various types of audio devices. In particular, portable audio reproducing devices, such as MP3 players, mobile phones having a music reproduction function, etc., which store hundreds to thousands of music tracks, have recently become popular. As a result, many people are listening to music using such portable audio reproducing devices.
Music stored in portable audio reproducing devices does not have the same level as recorded audio signals. Specifically, some music files can include high level audio signals, and other music files can include low level audio signals. Music including the high level audio signals produce loud sound, and music including the low level audio signals produce soft sound. In this regard, music including extremely low level audio signals does not produce a sufficient volume of sound even if the volume is turned up. This insufficient volume degrades the listening environment.
Portable audio reproducing devices have embedded batteries to supply voltage for portable terminals. As time elapses, the battery voltage for portable terminals is reduced. As the voltage supplied by the battery decreases, the volume level of the audio signal decreases. As a result, reproduced music sound becomes softer, resulting in a poor listening environment. Conventionally, when a low volume level audio signal is input or a battery supplies a lower voltage to a portable terminal, a reproduced music sound becomes softer, creating a poor listening environment.